Heat oven to 450 degrees.
Coat a large baking pan with non-stick cooking spray. Place fillet in pan, skin side down.
Spread cheese over top of fillet. Chop walnuts; press walnuts into cheese.
Bake in upper one-third of oven 8 to 12 minutes, depending on thickness (rule of thumb: 10
minutes per inch of thickness). Remove when fish just begins to flake with a fork, color
turns from translucent to opaque, or until a meat thermometer inserted horizontally into t
he thickest part reads 150 degrees. Cut into 4 portions and serve immediately.